Hem
The finished bottom edge of a garment or sleeve, made by folding the fabric over and stitching it.
The pattern includes a hem allowance, the extra length that is folded up, which is usually wider than the seam allowance. The depth depends on the garment and the fabric: narrow for light fabrics and deeper for pants or coats. On curved or flared hems the allowance is shaped so that the folded edge lies flat.
Example
A skirt with a 3 cm finished hem needs at least 3 cm of extra length added below the finished hem line.